In two experiments, 18 specific-pathogen free (SPF) lambs were inoculated by several routes with the Scottish strain of caprine herpesvirus 1 (CHV 1). Seventeen of the lambs developed interstitial changes in the lungs ranging from focal cellular infiltration to a widespread proliferative pneumonia. Five weeks after the initial inoculation 3 lambs were given a course of corticosteroid by intravenous injection. Subsequently virus was reisolated from all 3 lambs. Virus was also recovered from one of these lambs on one occasion prior to steroid treatment. It has therefore been established that CHV 1 can cause pneumonia and can be reisolated from infected sheep for at least 6 weeks after infection. It is suggested that CHV 1 might cause a latent infection in sheep which is reactivated following the development of pulmonary adenomatosis.